Flaw detector for knitting machines



1954 J. w. PHILLIPS ET AL 6 7 FLAW DETECTOR FOR KNITTING MACHINES Filed Sept. 16, 1947 5 Sheets-Sheet l INVENTORS.

3 Ja/zzz, CZ. 2301412? Z67. BY

1954 J. w. PHILLIPS ET AL 2,669,107

FLAW DETECTOR FOR KNITTING MACHINES Filed Sept. 16, 1947 3 Sheets-Sheet 2 ZIZ Z10 ]NVEN TOR.S.

QM]; Ql 21 074572 Feb. 16, 1954 J. W. PHILLIPS ET AL FLAW DETECTOR FOR KNITTING MACHINES 3 Sheets-Sheet 3 Filed Sept. 16, 1947 Patented Feb. 16, 1954 FLAW DETECTOR FOR KNITTING MACHINES John W. Phillips, Kenosha, Wis., and John A. Roush, Evanston, Ill., assignors, by direct and mesne assignments, to Coopers, Incorporated, Kenosha, Wis., a corporation of Wisconsin Application September 16, 1947, Serial No. 774,384

Claims.

This invention relates to a flaw detector and counter for a knitting machine, and to a method of detecting flaws in a knitted fabric. More particularly it relates to a detector and counter for a fabric knitting machine adapted to knit a continuous tube of fabric.

The principal object of this invention is to provide a flaw detector that will locate every flaw which justifies a garment cutter rejecting cloth as unsuitable for firsts garments. There have been both mechanical flaw detectors and photoelectric cell detectors but the applicant Phillips is not acquainted with any which will reliably detect a run. They, particularly the mechanical detectors, are designed to detect big cleave two horizontal supports, (that is the rungs of a ladder), make contact with the'electrode fover which the tube of fabric is moving, and

stop the machine and record a flaw.

A further second object of this invention is to relate the number of scanning fingers to the number of stitching stations on the revolving cylinder. This will be explained after themachine has been described.

Another object of the invention is to mount iii the testing finger so that there will be relative motion between it and the tube of knitted fabric.

This keeps the testing finger moving relative to the tube of fabric in a plane parallel to the plane of the movement of the stitching stations, and along a spiral with respect to the knitted tube. Expressed differently, the knitting proceeds along a spiral having a given pitch with respect to the axis of the fabric tube, and its relative motion such that the testing finger moves along the same spiral having a pitch with respect to the tube;

Applicants invention contains several features. Firstly, the testing finger assembly is a removable unit for testing one valley between two rows, and these units can be conveniently added to the flaw detector assembly as knitting stations are added to the cylinder. The testing finger contains a delicate but simply operated control for varying the pressure of the testing finger on the fabric. Each testing finger assembly contains a cam control for locking the finger out of ill) Applicants are considering placing a washable mark on the outside tube wall by a stamping device operated by the flaw detector. The purpose of this is to assist the garment cutter in avoiding errors. Some flaws are quite small and occasionally a garment maker misses them. Had he spotted the flaw at the time he made the gar- .ment, he could have cut itout as an arm or neck hole. This type of garment becomes a second and is sold as a second.

These and such other objects as may hereinafter appear are attained in the embodiment of the invention hereinafter described and shown in the accompanying drawings comprising three sheets wherein:

Fig. 1 is a view of a knitting machine illustrating the relationship of the flaw detector and counter to the machine with the wiring schematically shown;

Fig. '2 is a view in-eievation andpartly in crosssection of the flaw detectorwheel and associated parts with all of the knitting elements omitted,

however; i i

,Fig. 3 is a fragmentary bottom view of the flaw detector wheel;

Fig. iis an enlarged view of a piece of knitted fabric having typical holes therein; and,

Figs. 5 and 6 are somewhat diagrammatic views taken on the lines 5-5 and 66 of Fig. 4 respectively and showing the manner in which a vertically disposed testing finger I48 would operate at that point, and the manner in which a horizontally disposed testing finger I would operate at that point.

Referring now to the drawings, and particularly to Figure 4, a piece of fabric I, three times normal, unstretched size, is there shown, having .small defects thereinof the type which are most difficult to. detect. The piece of fabric l is a portion of a knitted tube or sleeve produced by a machine, having several knitting stations which successively knit along a line parallel to the line 2. Imperfections in the fabric are caused by a stuck latch on a needle, or a broken needle, or a heavy piece of yarn, and the defect may continue in the fabric until the machine operator discovers it and repairs the needle, or the machine may correct itself.

Againreferring to Figure 4, the fabric shown consists of ribs such as 3, each formed of what appears to be four vertical lines of thread, and spaced from each other by four parallel ladders, 4, 5, 6, and 1. If one turns the fabric inside out, the ladders 4, 5, G and 1 appear to be a rib like 3, while 3 appears to be four parallel ladders on the inside. 'When a needle which is handling the stitch at 8 sticks, the knitting machine does not jam, but simply skips the needle and continues to knit. At the point where this first occurs there is usually a rather pronounced hole 9.

gages the inside surface-of the fabric tube.

This hole is greater in width by reason of the disappearance of the stitching along; the line- 8, and it usually'ha's a geater height. In the illustration shown, the particular needle along the line 8 did not re-pickup with the result that there is a double width ladder H, which constitutes a fine run.

The hole I3 occurs in an outside rib, but inasmuch as the rib results from. a simple reversal of needles, the opening it is" exactly the same as the opening 9, with this important distinction,- for applicants flaw detector, that a mechanical scanning finger rides at a greater distance from its electric contact point when it is riding a rib that is projecting upwardly or outwardly toward it than when it is riding a ladder.

It will beobserved that the runs 1 l and idid notcorrect themselves, indicating a broken needle or a permanently stuck latch, and the machine will turn out imperfect cloth at the rate of several inches a minute until the operator notes the defect. An operator handles several machines, and a run arising from the failure of a single needle is difiicult to observe when you are standing four or five feet away from the cloth.

Continuing to refer to Figure 4, I! identifies a comparatively large opening caused by the failure of four'orfive needles on perhaps one or two revolutions of the cylinder. The latches momentarily stuck and then freed themselves. When the latches freed themselves, perfect knitting was resumed at point l9.

The defects illustrated in Figure 4 are the ones that applicants seek to detect. Big holes in the fabric are easily detected. A quarter or half inch opening in the fabric will be seen by the operator. Flaw detectors have been. able to catch these openings in the past, but they are not appreciably more effective than the operator and the applicant Phillips own mill does not use them. I

Referring now'to-Fig'". 1, the numeral l0 generally identifies' a circular fabric knitting machine which has a fixed table I 2, ashaft 46' (see Fig. 2) a cylinder carrying knitting equipment [4, a stationary dial member 2| (see Fig. 2), holders for spools of yarn l6, and various drive mechanisms and controls. Thus the numeral 40 refers to the prime mover; to which is rotatably secured the gear 4!. The cylinder and the shaft 46 are mounted for relative rotation therebetween. A tube of knitted fabric I8 is drawn downwardly from the cylinder by' pressure rolls 2'0 and'is fed onto a; bolt 22. The machine thus far described is standard mechanism and is available in a large number of specific for-ms. Generally, what applicants have done is to mount a wheel called the flaw detectorwheel 24 on the bottom of the shaft 46 so that the periphery of thewheel en- On the periphery of the wheel is mounted an electrically conductive finger 26. which fingeris pressed against the inside of the fabric tube. A conductor 28- is connected through an? electronic relay 30 to a source or power 32.

On. the outside of the fabric tube is an electricalIy conductive annulus" 34 which is connected by the conductor 36 through the electronic relay 30' to a source of power'3'2 when the circuit is closed by the finger 26' engaging the annulus 34. The said relay 30 is thus adapted to be activated by the said engagement of the finger 26 with the annulus 34 to open the power circuit from the line 32- to the said motor 40 so as to stop the 4 said motor. The annulus 34 carries an inwardly directed circular channel 58.

The flaw detector wheel 24 comprises a hub 60 from which radiate spokes 62 which support at their ends a rim 6-4. The rim 64 carries an outwardl-y directed circular channel 66 and the spacing is such that the testing finger rub line 88 is inside the channel 66 so that when the fabric" 10' is passed between the annulus 34 and the rim 6'4 the fabric will bear against the shoulders 12. and M which stretches the fabric tightly across the fabric rub line 68.

The wheel is drawn up tightly against the bottom of the shaft 46 by a sleeve bolt 16 pressing a Washer 78 against the bottom of the hub 60.

The dial member 2i does not rotate and suitable bearings 23 and 25 are provided between memher-21' and hub 86). It will be appreciated that the diameter of the wheel, the diameter of the hub journal, and the relationship of the rim to the hub may be varied to suit the particular machine to be equipped; On the knitting machine shown in these drawings; there is a cap having a shape very similar to the hub 60 mounted on the bottom of the shaft '46. Applicants replace this cap with the wheel.

The detector or switch comprises a fiber base 80 which is mounted on the top of one of the wheel spokes 62 by bolts'such as 82. Depending from the base 80' is a finger adjustment bracket comprisinga block 84' having'a' pair or vertically aligned transverse holes therethroughl In the upper hole is mounted an axially movable-plunger 86 which carries on its inner end a short stud 88. In'the lower hole is threadedly mounted a bolt 9'0 having ascrew driver "slot 92 and a disc head 9 which rides in the slot 96 in the plunger 86. By turning; the bolt 90, the plunger 86 may be moved in either direction axially, and the plunger 88" need not itself rotate. The finger 26 is pivotally' mounted on a shoulder screw 98 which is vertically positioned inthe base 80. Thefinger carries an inwardly directed dowel Hi9 in alignment with the stud. 88. An expansion spring I02 is disposed between the plunger 86 and the finger 2'6 and is held in position by the stud 88 and the dowel Hill. A cam I04 is mounted on a cam shaft [06 which carries on itsbottom a lever l08. The base 80 is drilled to receive a ball I. It pressed inwardly by a spring I] 2 which in turn is positioned by a set screw H4. Oppositely disposed sockets IIB are cut in the shaft I06 to receive ball l lilwhereby cam Hi4 may be selectively held in a position in which it holds finger 2'6 completely out of engagement-with the fabric or in a position in which finger 26 is permitted to fully engage the fabric.

Being able to hold the testing fingers away from the rub line 68 is important not only in settingup the machine, but after each time that a testing finger has stopped the machine. Referring to Fig. l, a testing finger is at approximatelyv the point indicated by thelead line" 34 While the knitting stations are at approximately a vertical distance thereabove of about four inches-on this particular type of machine. If the machine has been stopped by the beginning of a run, the run extends on up to the needles and it will be necessary to operate the machine until four inches of clear fabric have been knitted so as to reach the level of the testing fingers. During this time the testing fingers must be kept out of engagement. An alternativemethod is to connect up the circuit so that thereset button can be held closed when it is desired that .ing by means of a spring I a brush I38.

the testing fingers fail to function even though they engage the rub line 68. Electricity is carried to the finger 26 through screw 98 to which is fastened the conductor 2%,

which is carried up'axial hole 3| in the shaft 46 to a point above the knitting mechanism where it is carried out through passageway I26 to a slip ring I22. This slip ringis mounted by .a screw I24 and insulator I28 upon a ring I23,

which latter ring is standard equipment on the :particular machine applicants are using. Mounted on the table I2, at its edge, is a tubular post I30, on the upper end of which is a bracket I32 mounted on a horizontal pivot. The bracket supports a horizontally directed arm I34 carry- Depending upon the angle of the bracket I32 with respect to the post, the brush I38 may engage the slip ring I22 firmly or lightly.

In Fig. 3, two flaw detector units are shown. current reaching the second by means of the .conductor I40 and reaching a like finger unit on-the spoke I42 but not shown, by the conductor I44. A finger testing unit is desirable 'for each three or four knitting stations on the machine. =not confined to just one row but extends through Ordinarily when a hole occurs, it is several IOWS as a runner 01 even a large opening. The testing finger is following a spiral path around the inside of the tube and it is important s :that the spacing between the loops in that path be not so great that occasionally an appreciable hole might be missed. Consequently, if on each .rotation of the machine, the tube is being formed at the rate of about one-quarter of an inch of 1 fabric, it is desirable that more than one testing finger be used; It will be appreciated that the testing fingers will not overlap each other, that "is, will not describe exactly the same path, be- :cause all of them are mounted. in a common plane parallel to the plane of the knitting stations. In theory, by providing a testing finger ,for each knitting station, the testing finger would I move around parallel with one knitted row, and

would always be riding. in the valley between two knitted rows. This accuracy is not possible because the downward pull on the tube from below is not quite uniform. Each testing finger irregularly climbs over rows depending upon the regularity of the downward pull of the tubular fabric. At no time, however, is the pitch angle between the motion of a testing finger and the direction of a knitted row great enough to prevent the finger from dropping into an elongated opening such as 9 in Fig. 4.

Referring to Figs. 2 and 3, the tip I45 of the testing finger is very thin and very short so that -it will drop into an opening smaller than hole "9 in Fig. 4. The relay 35 is very sensitive and the said motor.

It will be understood that the knitting pro- 'ceeds along a line parallel tothe line 2 in Fig. l, "and that rows of knitting are parallel to that line. The knitting machine has several knitting stations on the cylinder 'so that the knitted rows are substantially horizontal although if examined in detail they would be spiral- Figure 5 illustrates why moving a testing finger at right angles to the rows (or parallel to the ribs) will not pick up a run while Figure 6 illustrates that moving the testing finger parallel to the rows (or at right angles to the ribs) will pick up a run. A run is caused by one or more needles not functioning and consequently a run extends at right angles to the knitted rows. There is no break in the yarn and consequently the spacing between the rows is the same whether there is a run or not. Thus, referring to Fig. 5 which is a view taken on the line 5-5 of Fig. 4, showing the testing finger I48 which is adapted to move at right angles to the rows (or parallel to the ribs) and has a testing head I50 which has a vertical height greater than the distance between two adjacent rows I52 and I54, but less than the distance between alternate rows I52 and I56. If the testing finger is moved vertically over the rows I52, I54, and 256, or if the fabric is moved over the testing finger in this manner, the testing finger will not detect a run, particularly where only one or two knitting needles have failed to function. The yarn at this particular point in the rows I 52, I54, and I 56 stretches tightly across the stretching surface and the yarn will support the head I and hold it out of engagement with the electrically conductive annulus. In Fig. 6, however, which is taken on the line ii-5 of Fig. 4, it is shown that the same form of 'the normal space between them.

Having thus described our invention, what we claim is:

l. A circular fabric knitting machine comprising a frame, a cylinder mounted thereon, knitting equipment mounted on the periphery of the cylinder, a shaft disposed on the axis of the cylinder,

said cylinder and said shaft being mounted for relative rotation therebetween, a flaw detector wheel mounted on said shaft. pressure rolls for drawing knitted fabric from the knitting cylinder over the flaw detector wheel as knitted, an

electrical conductive finger mounted on the periphery of the expander ring, an electrically conductive annulus mounted around the flaw detector wheel, the cross-sectional configuration of the inner surface of said annulus and of the peripheral edge of said expander ring being such that a portion of said peripheral edge extends into an interfitting relation with said inner surface and a portion of said inner surface likewise extends into interfitting relation with peripheral edge, conductors to the finger and the annulus forming a circuit when the finger engages the annulus, and means for stopping the machine disposed in circuit adapted to be activated when said finger engages said annulus.

' 2. The knitting machine described in claim 1 wherein the flaw detector wheel has an outwardly directed peripheral channel penetrated by the finger and the annulus has an annular rubline extending into the channel in lateral alignmen with the finger;

'3i The knitting machine described in claim 2 wherein the annulus has an annular inwardly directed shoulder on the upper side of the flaw detector wheel for additionally stretching the fabric.

4. The knitting machine of claim 1 wherein the conductor to the'finger extends up a hole in the shaft to apoint above the knitting stations and thence by brush and slip ring to the frame.

5. A flaw detector attachment for a circular fabric knitting machine having a center stem and a knitting cylinder mounted for relative rotation therebetween comprising a wheel for rigid mounting on the bottom of the said shaft, said wheel having a peripheral outwardly directed groove therein, an electrically conductive finger mounted on the periphery of the wheel, an electrically conductive I annulus-for mounting on the hired frame of the knitting machine around the wheel, said annulus having a cross-sectionalconifiguration such that a' portion thereof extends into interfitting relation with the'peripheral edge of said wheel, a spring urging. said finger against said portion of said annulus, electrical conductors forming a circuit through said finger and said annulus, and means for stopping the machine disposed in said circuit adapted to be activated when said finger engages said annulus.

6. In a circular fabric knitting machine adapted to produce a tube'of knitted fabric and having a flaw detector wheel and a knitting cylinde'r mounted-for relative rotation therebetwe'en, pressure rollers for drawing said knitted fabric from the knitting cylinder over the expander ring as knitted, an electrically conductive annulus positioned around the expander'ring, the adjacent surfaces of said expander ring and said annulus both having substantially complementary cross-"sectional configurations such that a portion of said annulus extends into inter'fitting relation with said expander ring, an electrically conductive finger mounted on the periphery of the expander ring inan engagea'ble relation with if the annulus, conductors to the finger and the annulus forming a circuit when the finger engages the annulus, and meansfor stopping the machine disposed in said circuit adapted to be activated when said finger engages said annulus.

7. A circular fabric knitting machinecomprising a frame, a cylinder mounted thereon, pressure I'OllGlSfOI holding the resulting tube of knitted fabric ata selected tension, a testing finger positioned inside the tube'of fabticand pressed against the interior surface thereof, the head of said testing finger having a width less than the distance between adjacent knitted rows and a length greater than the distance between adjacent stitches but less than the distance between alternated stitches, and said cylinder and said testing finger being mounted for relative rotation therebetween so that said testing finger moves around the inside of the tube along a line substantially parallel to the knitted rows.

8'. A fabric knitting machine comprising a frame, a cylinder mounted thereon, a vertical shaft, said cylinder and said shaft being mounted for relative rotation therebetween, a dial disposed on said shaft in association with and insecured relation to said cylinder, knitting equipment mounted on the periphery of said cylinder, a flaw detector wheel secured to said vertical shaft, means for drawing knitted-fabric from theknitting cylinder over the flaw detector wheel. as

knitted, an electrical conductive: finger. mounted on the periphery of-thcexpander ring; an electrically conductive annulus mounted "around" the flaw detector wheel-,sthe' cross -sectional configuration of the inner surface of said annulus and of the'peripheral ed'geof saidflawdetector wheel being such that a portionof said peripheral-edge extends into an interfitting relation with said inner surface and aportio'n of said inner-surface likewise extends into interfitting relation with peripheral edge, conductors to the finger and the annulus forming a circuit when the finger en'- gages the annulus,v and means for stopping the machine disposed in said circuit adapted. to be activatedwhen said-finger engages said annulus.

9. In a fabric knitting machine adapted to knit a continuous tube of fabric, a flaw detector 'whee l disposed so as to normally be within said tube of fabric, an annulus encircling said flaw detector wheel so'that said tube of fabric normally passes between said ring and said annulus, the adjacent Surfaces of said fia-w detector wheel and said annulus both having. substantially complemem tary cross-sectionalconfigurations such that a portion of said annulus extends into interfittin'g relation with said expander ring, and anelectrically conductive-detector finger disposed so as to normally bear' against said tube offabr ic at a point between said annulus and said flaw-detector wheel, means for producing. relative motion between said detector finger and said tube of fabric as said fabric is knitted,said detector finger being adapted to close an electrical circuit when it enters a flaw in the form of an opening. in said tube of fabric, and means for stopping the machine disposed in said circuit adapted to'be acti vatedwhen said finger engages said annulusa 10. In a fabric knitting: machine adaptedto knit a continuous tube'of fabr i'cyaflaw detector wheel disposed so as to normally bewithin said tube of fabric, an annulus encircling: said. flaw detector wheel so that said tube of fabric normally passes between said ring and said annulus, the adjacentsur'faces of said fiaw'detector wheel and said annulusboth having substantially com"- plementary cross sectional configurations such that a portion of said annulus extends into interfitting relation with said flaw detector wheel, means for producing relative motion-between said flaw detector wheel an-dsaid tube of fabricas said fa'bric is knitted, an electrically conductive detector finger disposed on said rotatable flaw detector wheel so as to normally bear against said tube of fabric at a' point between said annulus and said flaw detector wheel and to close an electrical: circuit when it enters a new in the Number Name Date 11,097,503 Anthony s Ma 19;19 1ii 1,784,446 Jennings i s: Dec-e, 1930 2,017,949 Cobb it Oct. 22, 1935 2,140,087 Nev/e11 which c Deals, 1938 2,357,712 Vossen Albumin Sept. 5,1944 2,357,714 Vossen et al. an--. Sept. 5, 19% 2,422,514- Allen: News is June 17, 1947 2,448,639 'Washsman swells Sept. '7, 1948 

